When a vehicle goes into a paint shop, for example for repainting of the body of a vehicle or a part thereof after repairs to the panelling following an accident, or for the purpose of touching up or decorating the vehicle, the work proves particularly difficult to perform at the borders between the bodywork to be painted and the neighbouring unpainted parts.
Thus, the glazed surfaces must be protected. They are usually covered with a paper screen, held by an adhesive tape fixed onto the seal along the perimeter of each window and of the windscreen.
The seal, generally made from rubber or from a semi-rigid plastic material, provides the leaktightness and simultaneously masks by covering the joining perimeter border between the edges of the windscreen and the bodywork. For this purpose, it covers the bodywork over a few millimetres.
In order to avoid an abrupt and unsightly discontinuity of the paint film at the edge of the lip of this seal, which promotes the start of flaking in the new coat of paint, it is necessary to raise the lip of the seal and to hold it raised during the spraying and drying of the paint.
It is thus possible to ensure continuity of the coat of paint under the covering lip of the seal.
In this manner, when the paint is sprayed, the spray also reaches the zone normally covered by the seal in a continuous manner.
In the final state, the seal therefore covers the border of the coat of paint, giving an aesthetic appearance of continuity and protecting this border against atmospheric corrosion.
In order to raise the lip of the seal and to hold it in the raised state over the entire perimeter of a windscreen or of a window, coachbuilders currently have available only makeshift means.
These are for example a linear insertion in the form of a flexible tubular pipe which is interposed between the lip of the seal and the bodywork by sliding it manually along the latter.
This tubular pipe may also be fitted using a guide which is introduced under the seal in order to raise it, and which is then slid along this seal all around the window. The tubular pipe slides in this guide in order to be laid down in the space existing between the seal and the bodywork.
This technique proves however to be unsatisfactory, because it has numerous drawbacks.
This tubular pipe manufactured for fluid linkages is available on the market only in certain sizes, for example five metres. Furthermore, its diameter proves to be ill-suited to the various types and widths of seals in existence.
Thus, when it is used for a small window, the remaining length must be gathered, wound, protected and fixed at the centre of the window while the painting stage is gone through, which requires additional handling operations.
Furthermore, it is necessary to have one piece of pipe for each window perimeter.
During the entire length of the painting and drying phase, it remains unavailable for a second coachbuilder.
As regards the actual use, these tubular pipes cannot provide a complete solution to all the difficulties of placing and of holding the lip of the seal in the raised state. It is particularly difficult to position the pipe so as to raise the lip of the seal evenly. In fact, the pipe squashes slightly then slides under the seal and wedges in an unordered manner because, in particular, of the play and of the variable surface condition of the gap existing between the windscreen and the bodywork. An irregularity of the border of the coat of paint therefore results.
In addition, the pipe tends to slide to the bottom of the groove between the seal and the bodywork, which leads to a raising of the lip of the seal which is still more irregular or unsatisfactory.
On the other hand, the pipe has a pronounced tendency to flatten or squash under mechanical stress, because of its tubular shape and a certain elasticity of the material from which it is made.
In addition, when this pipe is removed after the painting stage, it often remains glued by the paint. By the tearing force, small ridges therefore form, which, even when situated under the seal, may in the long term lead to the start of flaking of the new coat of paint.
Because of the expensive and impractical nature of this pipe, professionals often use a single electrical cable with its insulation, which is easily found on the market with different diameters suitable for various types of seals. However, this cable also becomes randomly placed under the seal, leading to irregular and variable raising of the latter. Furthermore, it is inconvenient to introduce under the seal. Finally, the coachbuilder must have a large number of different cables continuously in reserve.